Mineral oil composition



" Patented Dee. 3,1940

MIN RAL-01L 'ooMPos TIoN Everett W. Fuller, Woodb ton; Wenonah, N. J. VacuunrOil Company,

ury, and-Lyle A. Hamil assignors to 'Sooony- Incorporated, New York,

N. Y.,a corporation of New York NoDrawing. Application septem ereaieio,

. -Serial No;358,,832

17 Claims. (01. 25 2-50) 7 V7 p I V deposit sludge which interferes with heat trans- 7 f e This invention is concerned in a general way with the stabilization of viscous mineral oil fractions by the use of anovel class of compounds 2 or reaction products which when admixed'with 5 such a mineral ,oil inininor proportions will pre-' vent or delay undesirable changes taking'place in the oil.

As is Well known art, substantially all the" various 'fractions obtained from mineral oils andrefined for their various uses, are susceptible'to oxidation. The susceptibility of an oilfraction to oxidation and the manner in which oxidationmanifests itself within the oil varies with'the type and degree of refinement to which the oil has been subjected and with the conditions under" which it is used ortestedk In other words, the products formed inlan oil fraction as a result of oxidation and the degree to which thejex tentfto which the various unstable'con- 'stituent's' or constituents which may act'as oxidation 'catalysts have been removed'by refining op-' erations, and also upon the conditions of use.

A highly 'refined'viscous oil, for example, which fuming sulfuric acid or other means or-combinations such as A1C13, solvents and acids (or with large quantities of concentrated sulfuric acid),

as copper does not appear to affect appreciably the oxidation of highly refined oils, and such oils 1 are less promote the formation of colored" bodies or of insoluble sludge. The formation of acidic jbodies, however, is highly undesirable for most applications of these oils. For example, when used as an insulating or cooling oil in electrical equipment such as transformers or capacitors an 40 increase in acidic bodies tends to lower the dielectric strength of the oil and has other harmful eifects which are undesirable. rosive to metals and thus reduce the useful life of the oils as lubricants or for other purposes in v which they come in contact with metals, and, the

acidic materials are also injurious in textile lubricants and in spray oils.

vModerately refined oils-that is, oils that have been refined by treatment with only moderate amounts of sulfuric acid or other refining agents-tend to form relatively small amounts of acidic oxidation products as compared with highlyfrefine'd oils, but they undergo material color depreciation and form considerable amounts of sludge. The changes taking place in these oils are appreciably accelerated bythe presence ,of 'metal catalysts such as. copper. is generally formed to cause some reduction in the dielectric strength of these oils, but the prin- 60 cipal objection to them is their tendency to plugging of Sol'ir'ent-refined oils in generaLwhichhavebeen prepared by treatment with selective solvents} 'such as chlorex,'-phenol, furiural, etcgresemble.

to those mil s with the they are-formed depends upon is'one that has been refined by treatment with tends to form relatively large amounts of acidic constituents when subjected to oxidizing 'conj ditions. The presence of catalytic materials such 1 I any .one refining The acids are cor- Sufiicient acid fer in transformers and turbines andalso causes oil feed lines in lubricating, systems.

moderately refined acid-treated oils in that their oxidation is accelerated by the presence of metals such as" copper and further in that it is attended by substantial color depreciation and sludge' -for mation." Acid formation is usually greater. than inthecase of moderately acid-refined oils,

' but considerablyv less than .with highly refined oils. Both sludge and acid formation lowertheirvalue for many purposes, such as electrical insulation, lubrication, etc. Also, solvent-refined oils have'found extensive use as lubricants for internal combustion engines because of their high viscosity index, but

stituents which are corrosive .toward ,certain metaLbearings, such as the cadmium-silverbearing, etc., which are sometimes used. I

It is to be understood that this classification is by no means limiting and that there can exist oils whose refining and blending has been such as to make them intermediate in properties betweenthe types set up:-

hibitors may be said to type of oxidation and end products oioxidation of an oil, which in turn depends. largely upon thedegree of refining this oil hashad. Further, the degree of refining required to produce these types of oils varies with the crude source so that a highly refined oil or a moderately refined oil, depending upon the crude source. Pennsylvania type oils, for example, require much less refining procedure may produce either Z w under'rthe conditions of 'use' encountered in ci'arikcases such oils develop con- Thus, 'responseto independ entirelyupon the, V

to produce highly refined oils than the Coastal I type of oils. v V

The use of oxidation inhibitors for the purpose of stabilizing a viscous mineral oil fraction 7 against the deleterious effects of oxidation dis-.

cussed above is well known. Since the action of these inhibiting'materials is apparently catalytic, the problem of their development is a difficult oneand is evidently influenced to a large degree by the oxidizable constituents which are in the oil following a particular refining treatment.

7 Thus, a particular inhibitor or class ofrinhibitors may be effective to stabilize a highly refined. oil

against acid formation while the same inhibitor may have no appreciable efiect upon acid, color or sludgeforma'tion in a moderately refined oil, and viceversa. Thissame inhibitor may or may not be efiective in inhibiting acid, sludge or color formation in asolvent-refined oilandmay or may not be, effective to inhibit'the corrosive action of a solvent-refi such as used in cadmium-silver bearings,

ed oil toward metals 1 cov As indicated above. it is not uncommon to find an inhibiting agent or a class of inhibitingagents which is of practical effectiveness in only one of the various types of oil indicated above. One of 5 the outstanding characteristics of the compounds or reaction products contemplated by the present invention, however, is that this class of compounds is effective to inhibit the deleterious' effects of oxidation in each of the various types of viscous oils mentioned. They are also effective to inhibit acid formation in paraffin wax. Our invention, therefore, is directed broadly to petroleum products selected from the group consisting of viscous oils and paraffin wax as the mineral oil constituent of the composition of matter contemplated herein.

The particular field which shows the greatest promise for the immediate future and therefore constitutes the preferred class of compositions contemplated herein embraces viscous mineral oil fractions which have been refined to meet turbine oil or transformer oil specifications by one of the cheaper methods of refining such as light acid treatment or solvent-refining, which normally produce an oil of the so-called sludging type. As a preferred class of mineral oil compositions, therefore, our invention contemplates a normally sludging oil of the turbine or transformer type which contains a minor proportion of the novel inhibitor contemplated herein in an amount sufficient to retard the sludge formation.

The compounds or products contemplated herein as inhibitors for petroleum products fall into the general class of condensation products obtained by reacting amines with aldehydes. We are aware of the fact that this broad general class of compounds or reaction products has heretofore been suggested for use as inhibitors for mineral oils. Patent No. 1,594,983 discloses and claims the broad general class of condensation products obtained by reacting an aldehyde with a nitrogenous base, or more specifically, by reacting an aldehyde with an amine. The patent discloses these products as inhibitors for mineral oils. Although the patent contains a generic disclosure of the type just discussed, the only examples of amines used to illustrate the class of compounds contemplated by the patentee are primary amines; also the patentee indicates that all of the aldehydes are effective when reacted with amines to produce products of equivalent inhibiting powers.

Our invention is predicated upon the discovery that a specific aldehyde (formaldehyde) when reacted with a specific group of amines (secondary amines) produces inhibitors of surprisingly superior effectiveness as compared with the broad class represented by the primary amine reaction products of the type disclosed in the patent above referred to. More specifically, our invention contemplates the use of the condensation products obtained by reacting formaldehye with N-substituted arylamines. Novelty and distinction over the patent above referred to is predicated upon the discovery, first, that formaldehyde when reacted with N-substituted arylamines produces products superior in their inhibiting properties to the products obtained with the same amines and higher aldehydes, and, second, that the N-substituted arylamines when reacted with formaldehyde produce condensation products superior in their inhibiting properties to those obtained by reacting formaldehyde with primary amines.

The N-substituted.arylamines are compounds having the general formula in which R represents an aryl radical and R represents a radical selected from the group consisting of alkyl, alkaryl, aryl and aralkyl radicals. Examples of the N-substituted arylamines typified by the above general formula and contemplated herein for use as reactants with formaldehydes to obtain the, novel class of inhibitors are: N-methyl phenylamine, N-ethyl phenylamine, N-propyl phenylamine, N-butyl phenylamine, N-amyl phenylamine, N-butyl alpha-naphthylamine, N-benzyl phenylamine, diphenylamine, N-phenyl alpha-naphthylamine, N-phenyl beta-naphthylamine, and N-tolyl phenylamine.

The general procedure preferred for preparing the condensation products contemplated herein as inhibitors for petroleum compositions consists in first dissolving the secondary aromatic amine (N-substituted arylamine) in an alcohol and adding approximately one mole equivalent of hydrochloric acid. The mixture is then heated to a temperature of from 60 to C. and from one to two mole equivalents of formaldehyde are added. The heating is continued for a few hours, after which the reaction mixture is poured into water containing an excess of alkali such as NaOH, KOH or MIOH. The condensation product, which may be a solid or an oil, depending upon the amine used, separates from the water solution and may be purified by ordinary methods.

Modifications in the foregoing procedure may be made by changing the relative proportions of the reactants, by using other solvents or by carrying out the reaction under alkaline or neutral conditions rather than under acid conditions. For example, a typical modified procedure which wehave employed in making highly effective oil addition agents of the type contemplated herein involves reacting about one mole equivalent of an N-substituted arylamine with about one-half mole equivalent of formaldehyde in an aqueous solution containing about one mole equivalent of hydrochloric acid. The reaction is preferably carried out at elevated temperature. The temperature of the reaction may, of course, be varied,

as, for example, by permitting the reaction to proceed over a period of several days at room temperature. Further details in the procedure followed in synthesizing these products may be gathered from the following examples describing the synthesis of typical reaction products of the type which we have prepared to illustrate the effectiveness of these compounds.

EXAMPLE I pended in 200 cc. of ethyl alcohol, and 50 cc. of 5 per cent NI-LOH were added with stirring. The precipitate was filtered, washed with a little alcohol and then with water and dried. It gave a white powder that melted at about 205 C.

added, and the mixture was heated to a gentle reflux in a 1-liter flask with a stirrer, a water-' cooledcondenser and a dropping funnel. Eightytwo grams of 37. per cent formaldehyde (approx. 1.0 mole of CHgO). were addedfrom the dropping funnel in the course-of hour,and the mixture 'was then further heated to gentle reflux for 5 r hours. The contents of the flask 'were' poured Pinto 100000. of distilled water containing 200 cc.

" cous' brownpil thatwas miscible with petroleum oils. I

Ivarious petroleum products, including" various I I types of viscous mineral oils and parafiin wax, is illustrated by the'following examples: 2 v EXAM PLE III I HIGHLY Bnrmno (NQN-SLIlDGING) OILs The 'oil used in this test was of the typesuitable for use in transformers which had been highly refined from a Coastal distillate by treatment with 40 pounds of 98 per cent sulfuric acid, fol- Ilowed by 180' pounds of 103 per cent Oleum per I T as '1 point of 310 F.,and a Saybolt viscosity of '69 seconds at 100 F; 'I'he test involved 'heating'the' i "-mald ehydefwith the Ns ubstituted"arylamineinto I 1 I I I I lilonmiarnnx' BEFI'NED' (S LUnoINoy OrLs which had been refined to meet turbine oilspecificationsby treatment with 70 pounds of 98'per cent sulfuric acid per barreLIfollowed by neu-T;

tralization, water-washing and clay percolation.

Theo'il-had a specific gravity of0.879, a flash point of- 385, and a Saybolt viscosity of 152 sec- 79 onds at 100 F.

' The-test involved heating a 25 cc. sample of I the oil'to a temperature of 200i F. with 5 liters I of air per'hour bubbling therethrough Twenty 7, four inches of;18-gauge 'copperwire and -1 gram' 7 5 0; iron granules were added .to the oil sample,"

' -of .NH4OH solution. The oil that separated was} -I extracted with benzene, washed with water, dried f over CaClz, and the solvent was thenremoved bydl'smlation' Thls left 81 grams of rather wasformed in the inhibited sampledu'ring'a time h -interval many times greater. 1 ,I I I I The effectiveness of the condensation products Y contemplated herein as inhibitors of oxidation in:

lparrel, after which it was neutralized, washed, etc. It had a specific'gravityof 0.871, a flash condensation product obtained by reacting for- I s. as sees i The oil used in this test was one obtainedfrom 1 I a mixture of Mid-Continent and Coastal distillatesi fectiveness of the inhibitor can be observed by comparing the time intervaland the observed and 2 cc. of distilled water were added each day. I Y The samples were testedfor acidity, color and 'sludging after varying intervals of time. -IThe efproperties of the inhibited oils'and theoil alone in Table 2 below. 'It will be observed,Ifor example,

' that this oil containing 0.10 percent'ofthe condensation' product obtained by reacting formaldehyde' with'N-iso-amyl phenylamine, at the end of 1349 hours had a neutralization numberIKN.

N.) 01:32, a Lovibondcolor ofI22, and precipi- SOLVENT-REFINE) (SLUDGING) I One The oil used in thistest was one obtained from a mixture of'Mld-Continent and Coastal distillates which had been solvent-refined with furfural to a. 25 per cent loss. It had an A. P. I. gravity oi? 31.8 and a Saybolt viscosity of 136seconds at a 100 F. The test employed was the same as that described under Example IV above, and the re-; suits thereof are recorded in Table 3 below, a

a I t septum-Barium) Moron One 7 A' furtherIexample of-- the stabilizing action of the condensation products obtained by reacting 1 Table 2 I I Time in :Lovi. Slud e I Sample I hours color mg./25 cc..

Oil alone. 89 1.1 34 54 305 3.6 100 148 011+.10 0 product from I I forma dehyde and N- I isoamylphenylamine '366 .02 2.5 I 3 I 1349 .32 22 23 01l+ .i07 product from N-methy phenylaminefl 645 .34 I 16 011- l- .10% p roduct l'rom I I N-benzyl pheuylamine.. 307 .0l 2 8, 0i1+ .107 product from 1 I -I N-phenyi alpha-naph- 01l+ '.10% product from I I V N-phenyl beta-naphthyl- I v j amine II307 V .01- 10 I 1 1 M EXAMPLE V I .I Table 3 I x I a I Timeiri 'Lovl. Sludge onsample' hours color mg./25cc.

I 96 1.0 10 81.- m-re- 161 in v as 127 I I 237 21.2 285 799 0il+.10% of product from 366 .02, 2. 4 lormaldehydeIand N-iso- 72L 7 I03 2.31:- I '5 emyl phenylamine 1349 1.6' '35 47 I 01l+ .107- product from I formalde yde and 'N- y I I I methyl phenylaminduu 6 Li 26 1 322- -0ii+ 7 product from e iormaldefl de and di- I a j I I fihenylam no 307 2.4 42 37 O .10.7 product from 7 I I formaldehyde and N- {i benzylphenylamine. 307 07 2.4 15 0il+ .107 product from I I formalde yde and N- I Iphenyl -alpha-naphthyl- I I I I ofiigeia yhnndurfun 645 .75 27 I 173 1 prouc rom'i. -I, formaldehyde. and N- I phenyl beta-naphthyl-I I amine. 1 I307 .01; I 7 'I 13 formaldehyde with N-substituted arylamines is shown by the following test results. The oil used in this test was an S. A. E. 20 motor'oil made by solvent-extracting a Pennsylvania. neutral stock and a Pennsylvania residual stock with chlorex and then blending to the required viscosity. The test procedure involved immersing a section of a connecting rod bearing containing a cadmium-silver alloy surface and weighing about 6.0 grams in grams of oil. The oil was heated to a temperature of 175 F. for 22 hours While a stream of air was bubbled against the surface of the bearing. The weight loss of the bearing during this treatment measures the amount of corrosion that has taken place. In carrying out these tests a-sample of the oil containing one of the specified reaction products was run simultaneously with a sample of the uninhibited oil, each sample containing a section cut from the same hearing. The loss in weight of the bearing in the inhibited sample of oil can thus be compared directly with the loss of Weight in the bearing in the corresponding uninhibited sample. The results of this testare tabulated below in Table 4, in which it will be observed that tests were in several instances conducted with the same inhibitor in different proportions.

Table 4 Mg. loss in weight Inhibited oil sample Inhibited Uninhibited Oil+.l0% product from formaldehyde and N-methyl phenylamine 0 52 Oil+.05% product from N-methyl Oil+.l0%; product from formaldehyde and N-phenyl beta-napthylamine 0 52 Oil+.05% product from formaldehyde and N phenyl beta-naphthylaminenh 3 69 Oil+ .l0% product from formaldehyde and N-henzyl plienylainine 0 74 Oil+ l0% product from formaldehyde and diphenylamine 0 74 Oil+ .25';l product from formaldehyde and N plienyl alpha-naphthylainine l 74 EXAMPLE VII In this test the procedure followed was the same as that described above in Example III, and the oilused had been refined in the same way to meet the same specifications. The oil alone had a neutralization number in the neighborhood of 25, and the results obtained from blends of this oil containing reaction products of formaldehyde and typical primary amines are listed in Table 5A 7 below, the corresponding results obtained with the same oil containing reaction products of formaldehyde and typical N-substituted arylamines being listed in Table 53 below. It will be observed from the results in these tables that the reaction products of the primary amines are in three instances practically ineffective to inhibit acid formation in the highly refined oil, and in the case of the reaction product of the ringsubstitutedv tertiary amyl aniline the neutralization number of the oil after the test was from 50 to times greater than the neutralization numher of the samples containing the secondary amine reaction products.

Table 5A Naturali- Oll sample zation number Oll+ 10% product from formaldehyde and anilinem 20. 7 Orl+ .l0% product from formaldehyde and alphanaphthylamine 20. 9 Oil+.10% product from formaldehyde and C-p-tert.-

amyl aniline l. l Oil+.l0% product from formaldehyde and C-dodecy] aniline 19. 6

Table 5B Neutrali- 011 sample zatlon number 0il+ .l0% product from formaldehyde and N-methyl phenylamine 0.01 Oil+.l0% product from formaldehyde and N-iso-amyl phenylamiue 0.01 Oil+ .l0% product from N-benzyl phenylamine and 0iflormaldc yde 0.01 alpha-naphthylamine; 0.02 Oil+ .10% product from formaldehyde and N -phenyl betzi-naphthylamine 0.01 0il+.10% product from formaldehyde and N-butyl alpha-naphthylamine 0.00

EXAMPLE VIII In this test a solvent-refined turbine oil obtained by furfural extraction of Rodessa crude and having a specific gravity of .865, a flash point of 420 F., and Saybolt viscosity of 157 seconds at 100 F. was subjected to the same test described in Example IV. The results of this test for the oil alone are given below in Table 6A, the results for the same oil containing reaction products of formaldehyde with representative primary amines being given in Table 6B, and the results for oil blends containing reaction products of formaldehyde with secondary amylamines or N-substituted arylamines are given in Table 6C below.

Table 6A Time in Lovi. Sludge 011 Sample hours color mg./25 cc.

Table 6B Time in Lovl. Sludge 011 Sample hours N color mg./25 cc.

Oil+.l0% product from formaldehyde and Cptert-amylauilinc G8 0.43 8 172 V 163 25. 2 250 Oil+.l0% product from formaldehyde 8 n d C-dodecyl aniline 68 0. 49 8 216 163 23.0 400 206 ;t1on with Example v1 above.

4 I 7 ,0il+.25%ofproductfromformaldehyde formed in the oil alone. When these results-are 7, "compared with those obtained in Table'6C over' v comparative or even much greatertime intervals,

' I it will be apparent that the condensation prod- 5:5 ucts contemplated hereinare many times more effective as inhibitors of oxidation than'the general class of products disclosedin the patent're ferred to above. Y

In this test the procedure renewed and-the oil used were similar to those described in connece Table 7A below shows the corrosion test resultson solvent-refined motor oil -containing-the reaction .productsoi formaldehyde and typical primary amines, and;

[Table 7B shows the corresponding results obs tai'ned with the reaction products or formalde 4 hyde the the N-substituted amines It is interesting to observe in connection with the data in I thesetables that the reaction productsobtained 7 from the primary amines actually acceleratedthe 5o corrosionot the cadmium-silver bearing surfaces, Y Y as compared with-i the reaction products of the p a secondary amines; (N-substituted arylamines),

whichin several instances completely eliminated v corrosion over the period of the test and in all 7C0 instances effected a material retardation ofcorrosion.

Table 7A Mg. loss in weight gets Uninhibited a Table to. rable'm 7 V 1 t V Mg.1ossin wt.

=Timein Levi. Sludge 011 1 Y R 1 'ousamplet 9 ml; mp6, Inhibited we bited $g2% gg il-i-.0ll% product from formaldehyde 7 I I th y hg l i Y 1 3 V 0 01 '1 '5 d N- t yl phenylamine 0.2 69 I I I 499 2' 52 Oil-Hi5 product from formaldehyde h Y f v Y and -ethyl(pheny1amine O 555 10 product from Y Oil+.01% Bro not from formaldehyde formaldehyde, and N I and N-et ylphenylamine 16 66 I mixed any! phnyb 0il+.05%product from formaldehyde J amine 0 01 1 7 and N-iso-amylphenylamine 0.2 69 8 153 Oll+ .l0% product from'formaldehyde Y 034. 0% p gduct {tom v fi yl min 0 74 7 formaldehyde and N 0il+.l0 product from formaldehyde 15 butyl alpha-naphthylaandN- heny-alpha-naphthylamrne... l 74 a mine 167 0. 01- 2 r17 -2 g gg ffi o 78 h y an I1 498 19 a V 63 0il+.l0 0 pro d uct r' fozmald l iyde' v and N-butyl alphanaphthylamine. 2 l 62 r 011G0 1? p rri dget irozn f t i rz ialdehyde 6 74 V r r 7 an B118 .From the results in the tables above it will be y p e Y observed that the reaction products from the pri-'- ,7 mary arylamlnes have little or no eflect-as'inp Y 9 FL I 1 l hibitors of the oil in question under this test; The As s poi te ut a ve. we h di ve ed 7 sample containing the ring-substituted 'dodecyl that the reaction p ts btained with formal: aniline; for example, at the end of 163 hours had Y dehyde and N-substituted la are IV OlIta acidity and, Lovibbnd color each e t standingsuperiority over.corresponding reaction than the corresponding valu'esin the oil alone at products Obtained with the l e ryth end f hours m amount f; sludge aminesand the higheraldehydes. This is demformed in the oil containing. the ring-substituted g g g fi flz gu ig y tg i aa dodecyl aniline was great [as the sludge boil e' f1sing l thy l ghefiganf i as12 32am:

reactant and formaldehydeacetaldehyde and e octylaldehyde, respectively, as the'aldehyde: re -t actants. Q r 1 L v Theresults of this comparative'test are set forth in Table 8 below; The oil, ituwill be recalled, gave a neutralization number at the end of the-test in the neighborhood of 25, and it will be observed from thedata that the condensation product using'tormaldehyde is'far superior in its inhibiting power to the correspondingv condensation productsobtained with the higher aldehydes.

T A similar comparative test using the same oil described under Example IV and' 'thej procedure" described in Example IV abovewas carried out to Y obtain the resultsindicated in Table 9 below, and another test employing a solvent-refined oil of the type describediri Example V above was car 7 rled out to obtain the comparative r'esults'shown ts i '50 in Table 10 below.

., 7 Table 9 Time in Lovi. Slud e Y hours color 'mg.I25 cc.

' Oilalone .;.r l '89 1.1 '34 M p 30 3.6] 100-- 7148 '0il+.10% product from V V formaldehyde Y and N- ethyl phenylamino. 163 .01 '3 a t 499 1.3 27 'Oil+.l0%productfromacetaldehyde and -N-ethyl Y 7 l a e phenylamine.;. 7 162 1.3 30 i6 7 a 9 $306 3.8 65 94 Oil+.l0% product from Y y Y octylaldehyde and p 7 Y N-ethy1phenylamine- 306 4.6

"' for petroleum fractions.

From the data presented above in Tables 9 and 10 it will be observed that the condensation products employing formaldehyde are much more effective as inhibitors of sludge formation in the normally sludging turbine oils than are the corresponding condensation products obtained with the higher aldehydes.

EXAMPLE XII To demonstrate the eifectiveness of the con-' densation products contemplated herein as inhibitors of the deleterious effects of oxidation upon parafiin wax, a refined parafiin wax having a'melting point of 126 F. was tested by heating to 120 C. for '70 hours with oxygen bubbling therethrough, after which the neutralization number of the wax was determined. In this test the uninhibited wax gave a neutralization number of 35.6 at the end of the test as compared with a sample of the same wax containing .10 per cent of N-n-butyl alpha-naphthyiamine-formaldehyde condensation product, which showed no acidity at the end of the test. A sample of the same Wax containing 0.10 per cent of N-amyl phenylamine-formaldehyde condensation product showed an acidity of 0.01 at the end of the test. I I' In the methods of preparation described in Examples I and II it will be observed that the reactants (the N-substituted arylamine and the formaldehyde) were used in about equal molecular proportions and that the solvent medium for the reaction mixture was an alcohol. -Asaforesaid, the procedure may be altered by varying the relative proportions of the reactants, by using other solvents, etc.; and reference was made hereinabove to a modification in which the reaction is carried out in aqueous solution and the ratio of mole equivalents of N-substituted arylamine to formaldehyde in the reaction mixture was of the order of one to onehalf. 7 i l I "'"l Preparations have been made following the general procedure last described above. The products are equal, if not superior, to the products obtained by the procedures of Examples I and II in their effectiveness as addition agents Materials obtained by this procedure have an advantage over those described in the fotegoing examples in that, be ing made withouttthe use of organic solvents, they may be more "easily synthesized, and their cost of manufacture is considerably less. Ma-

terials made by this procedure consist partly of bis-alkylamino-diphenyl methane (when made from N-alkyl phenylamine or N-alkyl aniline) and partly of higher boiling materials of unknown composition.

However, the unknown constituent of these products is equally effective in its stabilizing effect as the substituted diphenyl methane, and for that reason this aspect of the invention is not confined to a particular compound or class of compounds as the addition agents but, as aforesaid, is directed to, and is defined as, a reaction product.

Further details in the procedure which may be followed in preparing these reaction products without the use of an organic solvent may be obtained from the following example.

EXAMPLE XIII The reaction mixture was prepared by dissolving 48.4 grams (.4 mole) of N-ethyl aniline in 100 cc. of water containing 80 cc. of hydrochloric acid- (specific gravity 1.19) and then adding 16 grams of formaldehyde solution (.2 mole of CHzO). The mixture was heated on a steam bath for 31 hours, during which time a white precipitate formed during the first hour and then gradually dissolved, leaving a clear solution. The mixture was then made alkaline with 10 per cent NaOH solution and steam-distilled to remove any excess of ethyl aniline. The residue was extracted with benzene, washed with water, dried over CaClz and the solvent distilled off to yield 48 grams of reaction product, which was a viscous oil.

In a second preparation the same reaction mixture was heated to reflux temperature for 10 hours, then neutralized, washed and dried as above to yield 46 grams of a similar product.

When 40 grams of the first product described above was distilled under a vacuum of 2 mm., 28 grams of an oil was obtained that boiled at 210- 215 C. and contained 10.88 per cent nitrogen. The residue consisting of 12 grams of higher boiling materials contained 9.54 per cent nitrogen on analysis. The first fraction consisted essentially of 4, 4' bis-ethylamino-diphenyl methane, but the residue was a condensation product of unknown structure. Since both fractions are effective antioxidants, the term "reaction product as used herein includes either the reaction product in its entirety or an individual fraction thereof of the type obtained by a fractionation of the type last described above.

Typical reaction products obtained by the procedure of Example XIII have been blended with typical mineral oil fractions and tested for their Table 11 (HIGHLY REFINED, NON-SLUDGING OIL) Neutralizatou number Oi! sample Oil alone Oil-l;,10% N-rnethyl phenylamine-forrualdchydc produc Oil+.l0% N-ethyl phcnylaminc-formaldehyde product (fraction boiling 210 to 215 C. at 2 mm.) Oil+.10% N-ethy] phenylamine-formaldchyde product fraction boiling above 215 at 2 mm.)... Oil+.10% N-amyl phenylaminc-formaldchyde product... Oil-l-OVE N-butyl elpha-naphthylamitic-formaldehyde pro uc small.

" Table 12; I I

(MQDERAT ELY REFINED' (SLUDGING) 01L) Time, Lov. Sludgev on Sample hrs. color mg./25 cc.

' Oil alone 168 '.99 '25 17 I I .240 2.5 .110"; .246 336 16, 0 400 1282 O1i+.l0% N-methyl-phena e 1 ylamiue formaldehyde I 1 i product 164 .01 1 524 .01 2 18 Oi]+.10% N-ethyi-phenyl- .5 7' g 5 amine iormaldehyde. i; product (fraction boiling .210-215 C.at2mm.)..-. 164' .01 2 1 15. I 500 .4 12V 31 i q 1004- 2.1 52 10s 1 Oil+.l0%N-ethyl-p11enylj amine formaldehyde 7 product (fraction boiling above 215 C. at 2mm.) 164 .01 l' .10- 1 500 .01 7 2V 51 1 1004 2.0 50 133 v20 0i1+.l0%N-amyl-phenylamine-formaldehyde product 164 .02 2 14 500 1.4 50 68- 0il+.10% N-buytl-alpha- 1 naphthylamine formal dehyde product 162' .02 1 1 666 1:6 45 45 Table. 13

*(SOLVENT-REFINED (SLUDGING OILS) f Time, 'Lov. Sludge J Oilalone 92 .91 9 33 I Oil+.10% N-methylphenylamine formaldehyde 1 7 35 producL; 164 a .m 1 524 .01 1 25 0il+.05% N-ethyl phenylamine formaldehyde product (fraction boiling v 210-215 C. 8.112 mm.). 500 .01 1 a V 2012 .01 1 s Oil+.05%N-ethyl phenylamino 1- formaldehyde product (ii-action boiling above 215C. at 2 mm.) 500 0. 0 1 l9 a 2012 0.0 1 11 0il+.05% N-amyi phenylamine formaldehyde I product 500 .01 1 40 2014 .03 2 1 Oil+.02% N-butyi alpha- ,naphthylamine-rormal-' I dehyde product 498 .01 1 5ft Table 1.4 M

SOLVENT-REFINED MOTOR OILS V Mg.1ossinweight 1 Reaction product in oil gggz Inhibited, Uninhibited N-methylphenylamine-iorme aldehyde .25 '0 g 28'. N-ethy phenylamme-iormal- I Y 7 1 dehyde. (fraction -bo1ling r g N-ethylphenyiamine-iormeldehyde (fraction boiling above 215 C.) .25 0 30 N-amyl phenylamine-iormala dehyde .25 1 0 33 N-butyl alpha-naphthylamine-formaldehyde .25 0. -33 H I varied, depending upon the oil, the conditions of from about 0.01 per cent to about 1.0 per cent by weight of the 011.

As'indicated by the foregoing examples, theproportion of the improving agents or condense-'- tion products contemplated herein'necessary to eifect the desired inhibition ofv oxidation-effects is The amounts used may of course be amine-aldehyde reaction products as represented by products obtained from aldehydes generally and primary amines. It is upon this discovery that we base our claim to novelty and patenta- J bilityjand while we have herein described certain preferred procedures for obtaining these condensation "products and have illustrate'dthe;

products with those obtainedby several typical 'N-substituted arylamines, our inventionis 'not limited to any specific procedure or any'specific .N-substituted arylamine but includes within its scope such changes or'modifications either in procedure orin reactantsas may fairly come sisting of viscous mineral oil fractions and par'ai 'fin' wax; andginadmixture therewith a minor proportion, .suflicient to inhibit the deleterious effects of oxidation upon. said petroleum product,

of the condensation product" obtained by reacting' formaldehyde with an N-substitutedarylamine. 2. composition viscous mineral oil fraction and inadmixture therewith a: minor proportion, sufficient" to vin-- V hibit the deleterious effects of oxidation uponsaid' 'of matter J comprising a 7 As will appear "from the foregoing data g tlie condensationv products obtained by reacting' formaldehyde with N-substituted "arylamines are: of outstandingsuperiority to the general fclass' of mineral oil, of :the condensation product obtaine'df r by reacting formaldehyde with an N-substituted arylamine. V

3. A composition of matter comprising: a parafiin wax and in admixturetherewith'a minor proportion, sufiicient to inhibit the deleterious effects of oxidation upon said Wax, of the com densation product obtained by reacting formaldeccus mineral oil fraction and in admixture therewith a minor proportion, sufficientto' inhibit the. deleterious efiects of oxidation'upon said mineral 011,1 of the condensation product obtainedbyre: i l acting vformaldehyde with an N-substitutdaryl- 50 amine selected from the group consisting of N- methyl phenylamine; N-ethyl phenyla'miney'N amyl phenylamine; N-butyl alph'a-naphthylamine; N-benzyl phenylamine; .diphenyl-amine;

phenyl alphamaphthyla'rhin; and phenyl beta- .naphthylamine.

5. A, composition of matter comprising; a;

petroleumproductjselectedfrom the grouppon sistinglof viscous mineraloil fractions and paraffin wax, and in admixture therewith a minor proportion, sufiicient to inhibit the deleterious? efiects' of oxidation upon said'petroleum prodnot, of the condensation product obtained by re-, acting formaldehyde with an organic aminehaving the general formula I in which R represents an aryl radical and R" represents a radical selcctedfrom the grcupcon sisting of alkyl, 'alkaryl, aryl anda'ralkyl radicals.

cous mineral oil fraction and in admixture there- 6. A composition of matter comprising: a vis-' 7 with a minor proportion, sufficient to inhibit the deleterious eilects of oxidation upon said oil, of -the condensation product obtained byreacting formaldehyde with an amine having the general formula I in which R represents an aryl radical and R represents a radical selected from the group consisting of alkyl, alkaryl, aryl and aralkyl radicals.

7. A composition of matter comprising: a parafiin wax and in admixture therewith a minor 15 proportion, sufiicient to inhibit the deleterious effects of oxidation upon said wax, of the condensation product obtained by reacting formaldehyde with an amine having the general formula tained by reacting formaldehyde with an N- substituted arylamine.

9. A composition of matter comprising a vis-' cous mineral oil fraction and in admixture therewith a minor proportion, from about 0.01 per cent to about 1.0 per cent, of the condensation product obtained by reacting formaldehyde with an amine selected from the group consisting of 4 N-methyl phenylamine; N-ethyl phenylamine;

N-amyl phenylamine; N-butyl alpha-naphthylamine; N-benzyl phenylamine; diphenylamine; phenyl alpha-naphthylamine; and phenyl betanaphthylamine.

45 10. A composition of matter comprising: a pctroleum product selected from the group consisting of viscous mineral oil fractions and paraffin wax, and in admixture therewith a minor proportion, from about 0.1 per cent to about 1.0 60 per cent, of the condensation product obtained by reacting formaldehyde with an organic amine having the general formula in which R represents an aryl radical and R represents a radical selected from the group consisting of alkyl, alkaryl, aryl and aralkyl radicals.

11. A mineral oil composition of the type adapted for use in turbines and transformers comprising a refined mineral oil fraction normally susceptible to the formation of sludge un- 65 der the conditions of use normally encountered in turbines and transformers anda minor proportion of the condensation product obtained by the reaction of formaldehyde with an N'-substi tuted aromatic amine.

12. A mineral oil composition of the type adapted for use in turbines and transformers comprising a refined mineral oil fraction normally susceptible to the formation of sludge unphenylamine;

der the conditions of use normally encountered in turbines and transformers and a minor proportion of the condensation product obtained by the reaction of formaldehyde with an N-substituted aromatic amine selected from the group consisting of N-methyl phenylamine; N-ethyl N-amyl phenylamine; N-butyl alpha-naphthylamine; N-benzyl phenylamine; diphenylamine; phenyl alpha-naphthylamine; and phenyl beta-naphthylamine.

13. A mineral oil composition of the type adapted for use in turbines and transformers comprising a refined mineral oil fraction normally susceptible to the formation of sludge under the conditions of use normally encountered in turbines and transformers and a minor proportion of the condensation product obtained by the reaction of formaldehyde with an organic amine having the general formula in which R represents an aryl radical and R represents a radical selected from the group consisting of alkyl, alkaryl, aryl and aralkyl radicals.

14. A composition of matter comprising: a petroleum product selected from the group consisting of viscous mineral oil fractions and paraflin wax, and in admixture therewith a minor proportion, sufiicient to inhibit the deleterious effects of oxidation upon said petroleum product, of the condensation product obtained by reacting at elevated temperature about one mole equivalent of an N-substituted aryl amine and from one to two mole equivalents of formaldehyde in an alcohol solution containing about one mole equivalent of a mineral acid.

15. A composition of matter comprising: a pe troleum product selected from the group consisting of viscous mineral oil fractions and paraflin wax, and in admixture therewith a minor proportion, sufficient to inhibit the deleterious effects of oxidation upon said petroleum product, of the condensation product obtained by reacting at elevated temperature about one mole equivalent of an N-substituted aryl amine and about one half mole equivalent of formaldehyde in an aqueous solution containing about one mole equivalent of a mineral acid.

16. A composition of matter comprising: a viscous mineral oil fraction and in admixture therewith a minor proportion, sufllcient to inhibit the deleterious efl'ects of oxidation upon said oil of the condensation product obtained by reacting at elevated temperature about one mole equivalent of an N-substituted aryl amine and from one to two mole equivalents of formaldehyde in an alcohol solution containing about one mole equivalent of a mineral acid.

17. A composition of matter comprising: a viscous mineral oil fraction and in admixture therewith a minor proportion, suflicient to inhibit the deleterious effects of oxidation upon said oil, of the condensation product obtained by reacting at elevated temperature about one mole equivalent of an N-substituted aryl amine and about one-half mole equivalent of formaldehyde in an aqueous solution containing about one mole equivalent of a mineral cid.

EigETT W. FULLER. 5. A. HAMILTON. 

